The 1D ${\mathrm{Y}}_2{\mathrm{SiO}}_5$: ${\mathrm{Ce}}^{3+}$, ${\mathrm{Yb}}^{3+}$ nanobelt phosphors and nanobelts-poly-ethylene vinyl acetate (poly-EVA) composite films were fabricated to explore spectral conversion materials for improving the conversion efficiency of $c$-Si solar cell. Scanning electron microscope, x-ray diffraction, photoluminescence excitation, photoluminescence (PL), transmission and decay curves were employed to characterize the structure, morphology, and optical properties. The nanobelt phosphor exhibits efficient ultraviolet (UV) absorption and gives intense near-infrared (NIR) emission. The UV to NIR downconversion process in ${\mathrm{Y}}_2{\mathrm{SiO}}_5$: ${\mathrm{Ce}}^{3+}$, ${\mathrm{Yb}}^{3+}$ nanobelts was investigated. More importantly, the thickness, transmission and PL spectra of nanobelts-poly-EVA films were also studied in detail. The NIR-emitting one-dimensional nanobelt-composite film may be applied as a promising spectral conversion layer for $c$-Si solar cell.